Buggy code:
class WeldSubsystemAdd extends AbstractBoottimeAddStepHandler { static final WeldSubsystemAdd INSTANCE = new WeldSubsystemAdd ( ) ; @ Override protected void populateModel ( ModelNode operation , ModelNode model ) throws OperationFailedException { } @ Override protected void performBoottime ( OperationContext context , ModelNode operation , final ModelNode model , ServiceVerificationHandler verificationHandler , List < ServiceController < ? > > newControllers ) throws OperationFailedException { final boolean requireBeanDescriptor = WeldResourceDefinition . REQUIRE_BEAN_DESCRIPTOR_ATTRIBUTE . resolveModelAttribute ( context , model ) . asBoolean ( ) ; final boolean nonPortableMode = NON_PORTABLE_MODE_ATTRIBUTE . resolveModelAttribute ( context , model ) . asBoolean ( ) ; context . addStep ( new AbstractDeploymentChainStep ( ) { @ Override protected void execute ( DeploymentProcessorTarget processorTarget ) { <START_BUG> processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , STRUCTURE , STRUCTURE_REGISTER_JBOSS_ALL_XML_PARSER , new org . jboss . as . server . deployment . jbossallxml . JBossAllXmlParserRegisteringProcessor ( WeldJBossAllParser . ROOT_ELEMENT , WeldJBossAllConfiguration . ATTACHMENT_KEY , WeldJBossAllParser . INSTANCE ) ) ; <END_BUG> processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , PARSE , PARSE_WELD_CONFIGURATION , new WeldConfigurationProcessor ( requireBeanDescriptor , nonPortableMode ) ) ; processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , PARSE , PARSE_CDI_ANNOTATIONS , new CdiAnnotationProcessor ( ) ) ; processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , PARSE , PARSE_CDI_BEAN_DEFINING_ANNOTATIONS , new BeanDefiningAnnotationProcessor ( ) ) ; processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , PARSE , PARSE_WELD_DEPLOYMENT , new BeansXmlProcessor ( ) ) ; processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , PARSE , PARSE_WELD_IMPLICIT_DEPLOYMENT_DETECTION , new WeldImplicitDeploymentProcessor ( ) ) ; processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , DEPENDENCIES , DEPENDENCIES_WELD , new WeldDependencyProcessor ( ) ) ; processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , POST_MODULE , POST_MODULE_WELD_WEB_INTEGRATION , new WebIntegrationProcessor ( ) ) ; processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , POST_MODULE , POST_MODULE_WELD_BEAN_ARCHIVE , new BeanArchiveProcessor ( ) ) ; processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , POST_MODULE , POST_MODULE_WELD_EXTERNAL_BEAN_ARCHIVE , new ExternalBeanArchiveProcessor ( ) ) ; processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , POST_MODULE , POST_MODULE_WELD_PORTABLE_EXTENSIONS , new WeldPortableExtensionProcessor ( ) ) ; processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , POST_MODULE , POST_MODULE_WELD_COMPONENT_INTEGRATION , new WeldComponentIntegrationProcessor ( ) ) ; processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , INSTALL , INSTALL_WELD_DEPLOYMENT , new WeldDeploymentProcessor ( ) ) ; processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , INSTALL , INSTALL_CDI_VALIDATOR_FACTORY , new CdiBeanValidationFactoryProcessor ( ) ) ; processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , INSTALL , INSTALL_WELD_BEAN_MANAGER , new WeldBeanManagerServiceProcessor ( ) ) ; } } , RUNTIME ) ; TCCLSingletonService singleton = new TCCLSingletonService ( ) ; newControllers . add ( context . getServiceTarget ( ) . addService ( SERVICE_NAME , singleton ) . setInitialMode ( ON_DEMAND ) . install ( ) ) ; } @ Override protected boolean requiresRuntimeVerification ( ) { } }

Fix:
processorTarget . addDeploymentProcessor ( SUBSYSTEM_NAME , STRUCTURE , STRUCTURE_REGISTER_JBOSS_ALL_WELD , new org . jboss . as . server . deployment . jbossallxml . JBossAllXmlParserRegisteringProcessor ( WeldJBossAllParser . ROOT_ELEMENT , WeldJBossAllConfiguration . ATTACHMENT_KEY , WeldJBossAllParser . INSTANCE ) ) ;